Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles

Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles Radioactivity in the environment chapter 15 moral dilemmas of uranium and thorium fuel cycles

Assumptions Concerning Reprocessing 270

15.4 Is Thorium a Viable Substitute or Supplement for Nuclear Fuel? 273

15.4.1 Proliferation Resistance:

Using Thorium

to Produce Less Plutonium 274 15.4.2 Waste-Management Benefits of Using Thorium in Molten Salt Reactors 275 15.4.3 Challenges and Shortcomings

of Thorium Cycles 275

15.5 Conclusions 277

15.1 INTRODUCTION

Recent developments in Germany’s energy policy aptly symbolize the versies surrounding the nuclear power debate In August 2010, after months of debate and consideration, Chancellor Merkel’s administration decided to extend the lifetime of Germany’s 17 nuclear power plants Surprisingly, Germany was also the first country in the world to revise its nuclear power policy, following the disastrous Fukushima-Daiichi events of March 2011 Simultaneously, the worldwide debate on the extent to which nuclear power should have a role in supplying our energy demands continues

contro-While increasingly more states are being swayed by the fact that nuclear power can enhance domestic energy security, boost energy levels, and reduce greenhouse gas byproducts, critics point to the continued risk of reactor accidents—Fukushima made this issue painfully clear—the dangers surround-ing nuclear fuel transportation, fears of proliferation and the vexing problem of how to deal with long-lived nuclear waste as reasons why it should be curtailed.But as politicians, energy experts and the general public weigh up the pros and cons, one key element linked to harnessing energy from the atom is being neglected: the relationship between the different nuclear power producing meth-ods (i.e fuel cycles) and the different safety, security, and economic consider-ations that each method brings The technical choices made today will not only determine the extent of the risk posed today, but they will also seriously affect the burden faced by humanity in the form of contaminated byproducts that can remain radiotoxic for hundreds of thousands of years Rather than reducing nuclear power to a simple yes/no, good/bad dichotomy, we need to first focus

on the advantages and disadvantages of each nuclear energy production method, including the burdens and benefits posed now and in generations to come.This will not, of course, answer the thorny question of whether we should

go nuclear on a larger scale or retain our current nuclear reactors We can only answer this question if we consider nuclear energy in relation to other energy sources We first have to distinguish between the different nuclear power pro-duction methods in terms of the different moral considerations they bring Such

analysis could help us to establish a desirable energy mix Not only does this

lend more accuracy to the debate but it also enables an ethically informed cussion to take place on the ideal future energy mix and the possible role of nuclear energy We need to include the new technology prospects and reflect

dis-on the desirability of future fuel cycles, the aim being to support research and development paths that could culminate in the industrialization of a certain desired technology This chapter will take up this challenge

In Section 15.2, I will first specify what is morally at stake in nuclear power production I will start by discussing the open fuel cycle, the most straightfor-ward and common type of nuclear power production I will identify several

of the moral values at stake Values are things worth striving for if we are to

achieve what we deem to be “good” Precisely what constitutes good in nuclear

power production has implications for different groups of people that are tially or temporally distinct I will discuss the four main values that play a key part in nuclear power production and waste management: safety (the public health impacts), security (sabotage and proliferation), sustainability (the envi-ronmental impacts and energy resource availability), and economic viability (embarking on new technology and its continuation).1 I will operationalize these values for different fuel cycles, by elaborating on how they relate to each step

spa-of the fuel cycle Section 15.3 extends these moral considerations by ing the closed fuel cycle that extends the open fuel cycle by recycling spent fuel after irradiation in a reactor Section 15.4 focuses on thorium as a possible nuclear fuel for the future Even though the relevance of thorium as a nuclear fuel has been acknowledged from the early days of nuclear power production,

includ-no thorium cycle yet exists Nevertheless, there is renewed interest in thorium because of its resource durability, but also because of the security enhancing and waste-management benefit prospects It is therefore important to include the future prospects of thorium as a substitute or as a complementary fuel and

to contemplate its ethical considerations Section 15.5 summarizes the findings made in this chapter

15.2 EXISTING NUCLEAR FUEL CYCLE: URANIUM

In this section I will first discuss the open fuel cycle2 type common in the U.S., Sweden, Canada, and many other countries I will then identify the four impor-tant values at stake and elaborate on how each step affects these values

The open fuel cycle consists of five main steps In Step 1, natural uranium is mined and milled, this process is similar to the mining of other metals, with the difference that uranium and its decay products emit ionizing radiation Step 2 involves the chemical purification and enrichment of uranium Natural uranium consists of the two main isotopes 235U and 238U Only the first isotope (235U)

is fissile and deployable as a fuel in currently operational Light Water Reactors

(LWR).3 However, this fissile uranium only constitutes 0.7% of all natural nium In order to produce a type of fuel that can be efficiently used in LWRs,

ura-we need to increase the content of this isotope to 3–5%; this process is known

as enrichment Enriched uranium4 is converted into uranium dioxide and used

to fabricate fuel (Step 3), which can be used in an LWR (Step 4) A typical fuel assembly will remain in the reactor for about four years; the remainder that is

1 For a detailed discussion of these values and how they have played a role in the history of nuclear reactor design, please see (Taebi & Kloosterman, in press).

2 The detailed information and figures about the open fuel cycle is based on two MIT reports (MIT,

discharged from the reactor is called spent fuel Spent fuel is not necessarily a

waste, but in the open fuel cycle it is disposed of as waste Before final disposal underground and in deep geological repositories (Step 5), spent fuel must be temporarily stored and cooled in storage facilities for several decades (Step 4)

In the remainder of this section, I will present a moral analysis of the open fuel cycle by first introducing the four main values at stake in nuclear energy pro-

duction; I will then operationalize these values by elaborating on the effect of

each step in the open fuel cycle

15.2.1 Safety

The IAEA et al (2006, p 5) defines public safety as “the safety of nuclear installations, radiation safety, the safety of radioactive waste management and safety in the transport of radioactive material.” Safety as a value refers here to those concerns that pertain to the exposure of the human body to radiation and

to the subsequent health effects.5 In radiation health, we distinguish between different types of radiation (α, β, γ and neutron radiation) and the various health effects It is both the nature of the radiation, the type of exposure (i.e inhalation, ingestion etc.) and the period of exposure that determines the radiotoxic effects

of any radiation (Smeesters, 2008) It is therefore important to include all types

of ionizing radiation in our moral analysis The general philosophy of radiation protection is “to reduce exposure to all types of ionizing radiations to the lowest possible level” (ICRP, 1959, p 10)

In all phases of the open fuel cycle, there is an ionizing radiation that has to

be coped with Though natural uranium emits fairly limited amounts of ionizing radiation, it is important to consider the steps 1 to 3 safety risks, because work-ers will be continuously exposed to such low-dose radiation.6 Furthermore, the disposal of uranium tailings in uranium mines, and depleted uranium around any uranium enrichment facility forms a major source of nuclear waste It is particularly the long-lived isotopes of radium (226Ra) and the gaseous decay product radon (Rn) that constitute health concerns for radiation workers.7 The high-dose radiation in the reactor is of a different type and also cause serious risks, due to the strong radioactive decay in the fuel; this radiation is shielded in the reactor The radiation emitted from spent fuel in the interim storage period

5 The IAEA et al (2006, p 5) defines safety as “the protection of people and the environment against radiation risks.” The radiation consequences for the environment and for nonhuman life will be returned to when the matters of sustainability and environmental friendliness are examined.

6 When referring to low-dose radiation, we really mean the probabilistic radiation effects: i.e the probability of severe consequences (e.g cancer) as a result of long-term exposure to such radiation (de Saint-Georges, 2008) For an overview of the occupational health standards, see (Hansson, 1998).

7 I owe this suggestion to Gilbert Eggermont and Jean Hugé who criticized my earlier publications

on this issue, in which I overlooked the health concerns of uranium mines and depleted uranium; see (Eggermont & Hugé, 2011, p 45).

(Step 4) also has to be carefully isolated, especially since serious decay and heat production occur during the first decades after fuel has been discharged from the reactor This is why repositories will not be permanently closed until 80–100 years after the emplacement of last loads of spent fuel The health effects of the alpha, beta, and gamma radiations in spent fuel are fairly known but what is less known is the effects of neutron radiation.8

In conjunction with the longevity of nuclear waste, safety is a value that specifically relates to future generations as well The safety of future genera-tions has been one of the concerns from the early days of nuclear power produc-tion (NRC, 1966) How we should protect future generations from the harmful effects of radiation remains a subject of an ongoing discussion, both in technical literature (how and where to build repositories that best guarantee long-term protection), and in policy-related documents The prevailing notion is that our responsibility to future generations will diminish over time which is why we do not have an obligation to offer the same level of protection to all future genera-tions In the US, this culminated in a policy to introduce a two-tiered standard

in order to distinguish between short-term and long-term radiological tions (EPA, 2005) However, this distinction lacks solid moral justification ( Shrader-Frechette, 1993, 2005; Taebi, 2012)

protec-As stated above, only 235U is fissile and deployable in light water reactors The major constituent of the fuel (238U) is fertile, meaning that upon absorb-

ing neutrons it converts to fissile 239Pu In addition to the unused 235U, 238U and 239Pu, spent fuel comprises other fissile and nonfissile plutonium isotopes,

and fission products Essentially, spent fuel poses a radiation risk throughout

the period of dangerous radioactive decay, something referred to as the waste lifetime, dominated by the presence of plutonium and americium In general, spent fuel is believed to be radiotoxic for a period of about 200,000 to one million years Precisely how we determine the waste lifetime remains a matter

of definition depending on the point of reference we choose Generally, when determining the waste lifetime, spent fuel is compared with the same amount of natural uranium, or uranium ore; it is the period after which the radiotoxicity of emitted radiation from spent fuel will reach the same radiotoxicity of that emit-ted by the same amount of natural uranium; see the dotted line in Figure 15.1.There have been at least two criticisms leveled at the way in which the radio-toxicity of nuclear waste has been compared to that of natural uranium ore Firstly, spent fuel consists of different chemical components to natural uranium, thus meaning that the effects on health of emitted radiation are not necessar-ily similar (Eggermont & Hugé, 2011, p 46) Secondly, natural radiation can

8 The energetic alpha particles released during the decay of the element americium (Am) could knock out neutrons from lighter elements such as oxygen (O) Furthermore, the spontaneous fission

of curium (Cm) could produce neutrons at an even higher rate (Wallenius, 2011) Americium and curium are two of the minor actinides produced during the irradiation of uranium fuel.

also cause serious health problems Therefore, referring to naturally caused radiation does not offer sufficient justification for tolerating comparable levels

of man-made radiation (Shrader-Frechette, 2005)

The waste lifetime denotes the period that nuclear waste needs to be lated from the environment So in addition to the uranium ore line, one can also use the peak-dose criterion In the US, a period of one million years was proposed by the National Academy of Science, which suggested that in terms

iso-of the nuclear waste produced in the US, the peak-dose will occur after 750,000 years The American regulator has endorsed one million years as the period of time necessary for the isolation of American waste (EPA, 2008).9

15.2.2 Security

In the IAEA’s Safety Glossary, nuclear security is defined as “any deliberate act directed against a nuclear facility or nuclear material in use, storage or transport, which could endanger the health and safety of the public or the environment”

to an extent, I shall keep the value of “security” separate so as to be able to distinguish between unintentional and intentional harm In an open fuel cycle, proliferation threats arise from the enrichment of uranium Uranium needs to

be enriched to 3–5% (and in some reactor types 20%) for power production purposes in reactors Highly Enriched Uranium (HEU) is produced by allowing

9 For an elaborate discussion of this issue see Chapter 8 in Vandenbosch and Vandenbosch (2007).

FIGURE 15.1 The radiotoxicity of spent fuel, high-level waste (HLW), and fission products,

compared to the radiotoxicity derived from the same amount of uranium ore.

the enrichment process to exceed 70%, a level only required for the ture of nuclear weapons The Hiroshima bomb dropped in 1945 was created from HEU When the enrichment exceeds 20%, the application can only be for nuclear arms; the IAEA has well-developed inspection methods to detect such activity in any facility under their control.

manufac-Serious contention concerning the expansion of civilian nuclear technology among new members is the matter of whether each country should have its own enrichment facility A good example is Iran, which insists on having its own enrichment facility While the Non-Proliferation Treaty gives all member states (including Iran) the right to follow through all steps of the nuclear fuel cycle, the existence of an enrichment facility clearly increases proliferation risks There are currently a few countries that operate enrichment facilities The countries that enrich impose limitations on the importing countries in order to avoid proliferation issues; the plutonium currently present in spent fuel constitutes a considerable proliferation risk too More will be said about this in Section 15.3

15.2.3 Sustainability

Sustainability is one of the most frequently discussed and perhaps contested notions in all the literature on nuclear power It is not my intention to enter into those discussions here and I certainly do not intend to assess the sustain-ability of nuclear power One common and influential definition concerning sustainable development is the Brundtland definition in which the ability of present generations to meet their own needs without compromising the abil-ity of future generations to meet their needs is emphasized (WCED, 1987) In nuclear power production and nuclear waste management, this definition relates

to at least two specific issues, namely the state of the environment bequeathed

by us to posterity—referred to as environmental friendliness—and the

avail-ability of natural (nonrenewable) energy resources on which future well-being

of generations relies, referred to as resource durability.

15.2.3.1 Environmental Friendliness

The value of environmental friendliness relates to the accompanying

radiologi-cal risks to the environment Radiologiradiologi-cal risks, as perceived in this chapter, express the possibility or rather the probability that radioactive nuclides might leak into the biosphere and harm both humans and the environment Issues that relate to the harming of human beings have already been subsumed under the heading safety The effect of the same radiation on the environment and non-human animals is included here under the heading of environmental friendli-ness Whether we should protect the environment for its own sake or for what

it means to human beings is a longstanding discussion that is still continuing

in environmental philosophy I do not intend to take a stance on this matter here I prefer to preserve the value of “environmental friendliness” as a sepa-rate value in order to allow a broader number of views to be reflected through

this set of values Those who adhere to the anthropocentric approach will then simply merge this value with the value of “safety”, while those who adhere to the nonanthropocentric approach will explicitly include in their analysis those risks and burdens other specifies will be exposed to as a result of humanity’s nuclear power production and consumption The latter could drastically change the ethical analysis.

be left no worse off […] than they would have been without depletion” (Barry,

1989, p 519) The value of resource durability is defined as the availability of

natural resources for the future or as the providing of an equivalent alternative (i.e compensation) for the same function In an open fuel cycle, we intend to use uranium and nuclear fuel only once The remaining spent fuel then officially has to be disposed of underground for a very long period of time Spent fuel contains various isotopes including uranium and plutonium that could also be used as fuel; this aspect will be discussed in Section 15.3

15.2.4 Economic Viability

The next value that we shall discuss in relation to sustainability is that of

moral relevance and whether it is justified to present economic durability as a moral value We can safely assume that the safeguarding of the general well-being of society (also, for instance, including health care issues) has undeniable moral relevance However, in my interpretation of economic viability in this chapter I do not refer to the general well-being but only to those aspects of well-being that have to do with nuclear energy production and consumption With this approach, economic aspects are not of inherent moral relevance; it is rather what stands to be achieved from such economic potential that makes it morally worthy

This is why the value of economic durability is presented in conjunction with other values First and foremost, economic viability should be considered

in connection with resource durability In that way, it relates to the economic potential for the initiation and continuation of an activity that produces nuclear energy As we shall see in the following sections, certain future nuclear energy production methods may well require serious R&D investments for further development; particularly new methods that are based on new types of reac-tors will require serious investment prior to industrialization Economic viabil-ity could also become a relevant notion when efforts are made to safeguard

the safety and security of posterity by introducing new technology designed to reduce the lifetime of nuclear waste In general, economic viability is defined here as the economic potential to embark on a new technology and to safeguard its continuation in order to uphold all the other values.

Since the open fuel cycle is the shortest cycle, in other words the one

neces-sitating least nuclear activity compared to the closed fuel cycle, we can argue that its economic burdens are low compared to other fuel cycles where spent fuel

is further recycled It should, however, be noted that since we do not yet have any geological repositories for the disposal of spent fuel, we cannot yet accu-rately estimate the costs of such a repository The legal requirements attached

to building such repositories could, for instance, impose additional technical criteria therefore making it more expensive than anticipated

15.3 THE CLOSED FUEL CYCLE AND INTERGENERATIONAL JUSTICE DILEMMAS

In Section 15.2, I briefly assessed the open fuel cycle on the basis of the four values of safety, security, sustainability, and economic viability In this section,

I will assess the main alternative for the open cycle, namely the closed fuel cycle, in terms of the same moral values With this cycle, spent fuel is no longer viewed as waste and the idea is to recycle it As stated above, less than 1% of the uranium ore consists of the fissile isotope 235U The major isotope of uranium (238U) is not fissile and it must be converted into fissile plutonium (239Pu) that

is deployable for energy production In the closed fuel cycle, spent fuel will undergo a chemical process to extract the useable elements, including pluto-

nium Such recycling treatment is referred to as reprocessing During

repro-cessing the uranium and plutonium isotopes in the spent fuel are isolated and recovered; the remaining materials are put into a glass matrix to be immobilized; this is known as High-Level Waste

There are two rationales to the closed fuel cycle Firstly, taking radiotoxicity

as a criterion, it could reduce the waste lifetime to c 10,000 years; ously the volume of the remaining High-Level Waste (HLW) could be reduced

simultane-by two-thirds Secondly, it will enable the more efficient use of nuclear fuel since recycled uranium could be added to the beginning of the fuel cycle The

extracted plutonium must be used for manufacturing Mixed Oxide Fuel (MOX ),

a nuclear fuel based on uranium and plutonium oxide MOX fuel is deployable

in the existing LWRs

Reprocessing is a technology as old as nuclear weapons themselves The first reprocessing plant was built as part of the Manhattan project in the US dur-ing the Second World War Its primary purpose was to extract plutonium from irradiated uranium fuel for use in nuclear weapons; that was to culminate in the Nagasaki bomb Worldwide, there are only five commercial reprocessing plants operable: namely in France, the U.K., Russia, India, and Japan Japan is the only nonweapon state that was building a reprocessing plant

15.3.1 Short-term Safety Compromised, while Long-term Safety

It should be noted that the risk of large quantities of radioactive waste being released during the transport of spent fuel and HLW is small; the countries concerned have extensive experience both with sea transport and rail transport

in Europe In view of the latter point, a 2006 U.S National Research Council report emphasized however that the vulnerability of this transport to terrorist attack need to be examined (NRC, 2006) As stated above, proliferation relates both to the dissemination of knowledge and technology on the manufacturing of nuclear weapons and to sabotage with radiotoxic materials

15.3.2 Additional Security Concerns in Conjunction with

To illustrate the seriousness of these proliferation risks, 8 kg of weapon-grade

plutonium (239Pu) is sufficient to produce a bomb with the devastation potential

of the Nagasaki bomb The kind of plutonium emerging from a power reactor under normal circumstances consists of different isotopes including 238Pu, 240Pu and 239Pu; Figure 15.2 shows the buildup of different plutonium isotopes during fuel irradiation For destructive purposes, plutonium must contain as much as

possible 239Pu; this corresponds to the relatively short burn up time, as illustrated

in Figure 15.2 Removing nuclear fuel after a couple of weeks of burning up

could thus be taken as evidence of ill intent While civilian plutonium does not

have the yield of weapon-grade plutonium it does carry serious security risks

To conclude, the closed fuel cycle seems to increase proliferation concerns

in the short term On the other hand, it reduces proliferation concerns in the long run because the material potentially deployable for proliferation (plutonium) will not be retained in the spent fuel Current spent fuel inventories are safeguarded

as well as military facilities, since this spent fuel contains plutonium

15.3.3 Resource Durability Enhanced, while Short-term

Environmental Friendliness is Compromised

In Section 15.2, I distinguished between two aspects of sustainability, namely resource durability and environmental friendliness The environmental aspects are closely related to the safety risks The closed fuel cycle seems to have seri-ous long-term safety (and thus environmental) benefits, but it brings with it various short-term safety and environmental concerns Regarding resource durability, reprocessing seems to create important benefits as well In the early days of nuclear energy production and after Eisenhower’s “Atoms for Peace” speech of 1953, reprocessing was promoted as the technology that could lead

to sufficient supplies of nuclear fuel Instead of using the uranium fuel once,

it would be used more efficiently Both the remaining uranium in spent fuel and the plutonium produced could be reused In the first years of commercial nuclear power developments in the 1960s all countries considered reprocessing

FIGURE 15.2 The burning up of different plutonium isotopes in an LWR Source: ( Taebi, 2012 )

(For color version of this figure, the reader is referred to the online version of this book.)